Zimbra + Amazon EC2 Questions

My understanding is EC2 instances are not permanent, once you term the instance everything resets. That is why "Volumes" come in to store perm data.

If I were to setup Zimbra on EC2 as a perm solution, would I take this route?

Setup instance using an existing AMI
Setup a Volume and Attach it to the AMI on /opt
Install Zimbra
Create my own AMI and save it to my personal AMI's.
Then continue to use my custom AMI w/ the static /opt volume mounted.

Am I correct in thinking this would be the right way to setup a perm Zimbra solution on EC2?